The present invention relates to semiconductor devices and relates to a technique applicable to a semiconductor device including a logic region, for example.
Presently, semiconductor devices are being miniaturized. Along with the miniaturization in a semiconductor device, the distance between the semiconductor element and a wiring and the distance between wirings become short. In this case, the parasitic capacitance formed between the semiconductor device and the wiring and the parasitic capacitance formed between the wirings come to affect the operation of the semiconductor device.
For example, in a transistor, sometimes a gate electrode and an LDD (Lightly-doped Drain) form the parasitic capacitance sandwiching a side wall. When the semiconductor element is miniaturized as above, such parasitic capacitance comes to affect the operation of the transistor. Accordingly, non-patent literature 1 (C. H. Ko, T. M. Kuan, Kangzhan Zhang, Gino Tsai, Sean M. Seutter, C. H. Wu, T. J. Wang, C. N. Ye, H. W. Chen, C. H. Ge, K. H. Wu, and W. C. Lee, “A Novel CVD-SiBCN Low-K Spacer Technology for High-Speed Applications”, 2008 Symposium on VLSI Technology Digest of Technical Papers, pp. 108-109.), for example, describes the use of a low-k material for the side wall. Specifically, SiBCN is used as the low-k material in non-patent literature 1. Thereby, it is possible to reduce the parasitic capacitance formed by the gate electrode, the LDD region, and the side wall.
Further, also in a NAND flash memory, sometimes parasitic capacitance is formed by neighboring cells. Such parasitic capacitance comes to affect memory operation along with the miniaturization of the cell. Accordingly, non-patent literature 2 (Daewoong Kang, Hyungcheol Shin, Sungnum Chang, Jungjoo An, Kyongjoo Lee, Jinjoo Kim, Eunsang Jeong, Hyukje Kwon, Eunjung Lee, Seunggun Seo, and Wonseong Lee. “The Air Spacer Technology for Improving the Cell Distribution in 1 Giga Bit NAND Flash Memory” Non-Volatile Semiconductor Memory Workshop, 2006. IEEE NVSMW 2006. 21st, pp. 36-37.), for example, describes the formation of an air space between the neighboring cells. Such an air space has a low dielectric constant. Therefore, it is possible to reduce the parasitic capacitance between the neighboring cells.